A Light Emitting Diode (LED) component includes a lead frame and an LED that is electrically connected to the lead frame without wire bonds, using a solder layer. The lead frame includes a metal anode pad, a metal cathode pad and a plastic cup. The LED die includes LED die anode and cathode contacts with a solder layer on them. The metal anode pad, metal cathode pad, plastic cup and/or the solder layer are configured to facilitate the direct die attach of the LED die to the lead frame without wire bonds. Related fabrication methods are also described.
Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A Light Emitting Diode (LED) component comprising: a lead frame that comprises a metal anode pad, a metal cathode pad and a plastic cup on the metal anode pad and the metal cathode pad that defines an exposed portion of the metal anode pad and an exposed portion of the metal cathode pad in an interior of the plastic cup, the plastic cup comprising: a plastic cup wall on a first face of the metal anode pad and a first face of the metal cathode pad to define the exposed portion of the metal anode pad and the exposed portion of the metal cathode pad in the interior of the plastic cup, and extending away from the metal anode pad and the metal cathode; a plastic cup base on a second face of the metal anode pad and a second face of the metal cathode pad that are opposite the first face and extending in a direction of the metal anode pad and the metal cathode pad to define an exposed portion of the second face of the metal anode pad and an exposed portion of the second face of the metal cathode pad to an exterior of the plastic cup; and a plastic cup opening remote from the plastic cup base; an LED die that comprises first and second opposing faces and an anode contact and a cathode contact on the first face thereof, the anode and cathode contacts including outer faces remote from the LED die, the LED die being disposed in the plastic cup such that the outer face of the anode contact is adjacent the plastic cup base and spaced apart from the exposed portion of the metal anode pad, and the outer face of the cathode contact is adjacent the plastic up base and spaced apart from the exposed portion of the metal cathode pad; and a die attach layer that extends between the outer face of the anode contact and the exposed portion of the metal anode pad and between the outer face of the cathode contact and the exposed portion of the metal cathode pad and that directly electrically connects the outer face of the anode contact to the exposed portion of the metal anode pad and directly electrically connects the outer face of the cathode contact to the exposed portion of the metal cathode pad.
An LED component consists of a lead frame and an LED die directly attached to it without wire bonds. The lead frame has a metal anode pad, a metal cathode pad, and a plastic cup sitting on top of both pads. The cup exposes portions of the pads inside its cavity. The cup has a wall on the front of the pads extending upwards and a base on the back of the pads extending downwards. This base exposes the back of the pads to the outside. The LED die has anode and cathode contacts on its front side. These contacts face towards the plastic cup base but are spaced slightly apart from the exposed metal pads. A die attach layer (e.g. solder) fills the gap, directly electrically connecting the LED die's anode contact to the metal anode pad and the LED die's cathode contact to the metal cathode pad.
2. The LED component according to claim 1 wherein the exposed portions of the metal anode and cathode pads are not coplanar.
The LED component, described previously, where an LED die is directly attached to a lead frame consisting of metal anode and cathode pads within a plastic cup using a die attach layer, has the added feature that the exposed surfaces of the metal anode and cathode pads inside the plastic cup are not on the same plane (not coplanar).
3. The LED component according to claim 1 wherein the plastic cup comprises silicone.
The LED component, described previously, where an LED die is directly attached to a lead frame consisting of metal anode and cathode pads within a plastic cup using a die attach layer, has the added feature that the plastic cup is made of silicone.
4. The LED component according to claim 1 wherein the metal anode pad, the metal cathode pad and/or the plastic cup are configured to facilitate the direct electrical connection of the outer face of the anode contact to the exposed portion of the metal anode pad and the direct electrical connection of the outer face of the cathode contact to the exposed portion of the metal cathode pad, by the die attach layer.
The LED component, described previously, where an LED die is directly attached to a lead frame consisting of metal anode and cathode pads within a plastic cup using a die attach layer, has the added feature that the shape and configuration of the metal pads and/or the plastic cup are specifically designed to make the direct electrical connection between the LED die and the lead frame easier and more reliable using the die attach layer.
5. The LED component according to claim 4 wherein adjacent ends of the metal anode pad and the metal cathode pad define a gap therebetween, wherein the plastic cup extends in the gap and also extends beyond non-adjacent ends of the metal anode pad and the metal cathode pad by a distance, and wherein the distance is larger than the gap.
The LED component with a lead frame containing metal anode and cathode pads inside a plastic cup, designed for direct LED die attachment and electrical connection as described before, has the following spatial arrangement: the metal anode and metal cathode pads have ends that nearly face each other creating a small gap in-between. The plastic cup extends into this gap, filling the space. Also, the cup extends beyond the other ends of the metal pads, beyond the gap ends. The length of this extension is larger than the width of the gap.
6. The LED component according to claim 5 wherein the distance is at least 10% larger than the gap.
The LED component described previously, with a plastic cup extending beyond the non-adjacent ends of the metal anode and cathode pads by a distance greater than the gap between adjacent ends, has the specific feature that this distance is at least 10% larger than the gap width.
7. The LED component according to claim 4 wherein adjacent ends of the metal anode pad and the metal cathode pad have different widths.
The LED component with a lead frame containing metal anode and cathode pads inside a plastic cup, designed for direct LED die attachment and electrical connection as described before, has the added feature that the adjacent ends of the metal anode pad and the metal cathode pad (the ends that are nearest each other) have different widths.
8. The LED component according to claim 4 wherein the lead frame further comprises a metal link that mechanically connects the metal anode pad to the metal cathode pad outside the plastic cup.
The LED component with a lead frame containing metal anode and cathode pads inside a plastic cup, designed for direct LED die attachment and electrical connection as described before, includes a metal link that physically connects the metal anode pad to the metal cathode pad. This link is located outside the area enclosed by the plastic cup.
9. The LED component according to claim 8 wherein the metal link is configured to be sheared from the metal anode pad and/or the metal cathode pad.
The LED component with a metal link physically connecting the metal anode pad to the metal cathode pad outside the plastic cup, as described previously, has the feature that the metal link is designed to be easily cut or sheared off from one or both of the metal pads.
10. The LED component according to claim 8 wherein the metal link comprises a fusible metal.
The LED component with a metal link physically connecting the metal anode pad to the metal cathode pad outside the plastic cup, as described previously, has the feature that the metal link is made of a metal that can be easily melted (a fusible metal).
11. The LED component according to claim 4 wherein adjacent ends of the metal anode pad and the metal cathode pad include curved facing surfaces.
The LED component with a lead frame containing metal anode and cathode pads inside a plastic cup, designed for direct LED die attachment and electrical connection as described before, has the feature that the ends of the metal anode pad and the metal cathode pad that face each other are curved.
12. The LED component according to claim 11 wherein the curved facing surfaces comprise a plurality of line segments that form oblique and/or orthogonal angles therebetween.
The LED component with curved surfaces on the facing ends of the metal pads, as described before, has the feature that these curved surfaces are actually made up of multiple straight line segments joined together, forming angled corners (oblique or orthogonal angles) between the segments.
13. The LED component according to claim 12 wherein the LED die is a first LED die disposed in the plastic cup such that the outer face of the anode contact is adjacent the plastic cup base and spaced apart from the metal anode pad adjacent a first one of the line segments, and the outer face of the cathode contact is adjacent the plastic cup base and spaced apart from the metal cathode pad adjacent the first one of the line segments; the LED component further comprising a second LED die that also comprises first and second opposing faces and an anode contact and a cathode contact on the first face thereof, the anode and cathode contacts including outer faces remote from the second LED die, the second LED die being disposed in the plastic cup such that the outer face of the anode contact is adjacent the plastic cup base and spaced apart from the metal anode pad adjacent a second one of the line segments, and the outer face of the cathode contact is adjacent the plastic cup base and spaced apart from the metal cathode pad adjacent the second one of the line segments.
The LED component with a lead frame containing metal anode and cathode pads inside a plastic cup, designed for direct LED die attachment and electrical connection as described before, where the curved facing surfaces on the pads are formed by multiple line segments, has the following feature: A first LED die is positioned so that its contacts are adjacent to a first line segment of each metal pad. The component further includes a second LED die. This second LED die is positioned so that its contacts are adjacent to a second, different line segment of each metal pad.
14. The LED component according to claim 4 wherein the metal anode pad includes a metal finger that extends toward the metal cathode pad and wherein the metal cathode pad includes a metal finger that extends toward the metal anode pad.
The LED component with a lead frame containing metal anode and cathode pads inside a plastic cup, designed for direct LED die attachment and electrical connection as described before, has the feature that the metal anode pad includes a metal "finger" that extends towards the metal cathode pad, and the metal cathode pad includes a metal "finger" that extends towards the metal anode pad.
15. The LED component according to claim 4 wherein one of the metal anode pad or the metal cathode pad includes three edges and the other of the metal cathode pad or the metal anode pad extends adjacent the three edges.
The LED component with a lead frame containing metal anode and cathode pads inside a plastic cup, designed for direct LED die attachment and electrical connection as described before, has the feature that one of the metal pads has three edges, and the other metal pad extends along those three edges.
16. The LED component according to claim 4 wherein one of the metal anode pad or the metal cathode pad includes four edges and the other of the metal cathode pad or the metal anode pad extends adjacent the four edges.
The LED component with a lead frame containing metal anode and cathode pads inside a plastic cup, designed for direct LED die attachment and electrical connection as described before, has the feature that one of the metal pads has four edges, and the other metal pad extends along those four edges.
17. The LED component according to claim 1 wherein the die attach layer is configured to facilitate the direct electrical connection of the outer face of the anode contact to the exposed portion of the metal anode pad and the direct electrical connection of the outer face of the cathode contact to the exposed portion of the metal cathode pad, by the die attach layer.
The LED component consists of a lead frame and an LED die directly attached to it without wire bonds. The lead frame has a metal anode pad, a metal cathode pad, and a plastic cup sitting on top of both pads. The cup exposes portions of the pads inside its cavity. The cup has a wall on the front of the pads extending upwards and a base on the back of the pads extending downwards. This base exposes the back of the pads to the outside. The LED die has anode and cathode contacts on its front side. These contacts face towards the plastic cup base but are spaced slightly apart from the exposed metal pads. The die attach layer is specifically formulated to allow for direct electrical connection by the die attach layer.
18. The LED component according to claim 17 : wherein the exposed portions of the metal anode and cathode pads deviate from coplanarity by a height difference, and wherein the die attach layer is thicker than the height difference.
The LED component, described previously, where an LED die is directly attached to a lead frame consisting of metal anode and cathode pads within a plastic cup using a die attach layer, where the die attach layer is specifically formulated to allow for direct electrical connection by the die attach layer, has the added feature that the exposed surfaces of the metal anode and cathode pads inside the plastic cup are not on the same plane, and the die attach layer is thicker than the height difference between the pads.
19. The LED component according to claim 18 wherein the die attach layer is also thicker than 3 μm.
The LED component where the die attach layer is thicker than the height difference between the exposed surfaces of the non-coplanar metal anode and cathode pads, as previously described, has the added feature that the die attach layer is also thicker than 3 micrometers.
20. The LED component according to claim 17 wherein the die attach layer is of different thickness between the outer face of the anode contact that is spaced apart from the exposed portion of the metal anode pad compared to between the outer face of the cathode contact that is spaced apart from the exposed portion of the metal cathode pad.
The LED component, described previously, where an LED die is directly attached to a lead frame consisting of metal anode and cathode pads within a plastic cup using a die attach layer, where the die attach layer is specifically formulated to allow for direct electrical connection by the die attach layer, has the added feature that the die attach layer has different thicknesses in the gaps between the anode contact and anode pad and between the cathode contact and cathode pad.
21. The LED component according to claim 17 wherein the die attach layer comprises a solder comprising Gold (Au), Nickel (Ni) and Tin (Sn).
The LED component, described previously, where an LED die is directly attached to a lead frame consisting of metal anode and cathode pads within a plastic cup using a die attach layer, where the die attach layer is specifically formulated to allow for direct electrical connection by the die attach layer, has the added feature that the die attach layer is a solder made of gold (Au), nickel (Ni), and tin (Sn).
22. The LED component according to claim 21 wherein 0<Au wt %≦10, 10≦Ni wt %≦60 and 40≦Sn wt %≦90.
The LED component where the die attach layer is a solder made of gold (Au), nickel (Ni), and tin (Sn), as previously described, has the added feature that the weight percentages of the metals are within these ranges: 0 < Au wt % <= 10, 10 <= Ni wt % <= 60, and 40 <= Sn wt % <= 90.
23. The LED component according to claim 22 wherein 0.8≦Au wt %≦4.5, 19≦Ni wt %≦41 and 55≦Sn wt %≦80.
The LED component where the die attach layer is a solder made of gold (Au), nickel (Ni), and tin (Sn), with weight percentages in the ranges specified before, has the added feature that the weight percentages are more specifically within these ranges: 0.8 <= Au wt % <= 4.5, 19 <= Ni wt % <= 41, and 55 <= Sn wt % <= 80.
24. The LED component according to claim 17 wherein the plastic cup comprises silicone and wherein the die attach layer has a melting temperature below a decomposition temperature of the silicone.
The LED component, described previously, where an LED die is directly attached to a lead frame consisting of metal anode and cathode pads within a plastic cup using a die attach layer, where the die attach layer is specifically formulated to allow for direct electrical connection by the die attach layer, has the added feature that the plastic cup is made of silicone and the die attach layer (solder) has a melting temperature that is lower than the temperature at which the silicone starts to decompose.
25. The LED component according to claim 17 wherein the die attach layer has a melting temperature below 260° C.
The LED component, described previously, where an LED die is directly attached to a lead frame consisting of metal anode and cathode pads within a plastic cup using a die attach layer, where the die attach layer is specifically formulated to allow for direct electrical connection by the die attach layer, has the added feature that the die attach layer has a melting temperature below 260 degrees Celsius.
26. The LED component according to claim 17 wherein the die attach layer has a melting temperature and has a re-melting temperature that is higher than the melting temperature.
The LED component, described previously, where an LED die is directly attached to a lead frame consisting of metal anode and cathode pads within a plastic cup using a die attach layer, where the die attach layer is specifically formulated to allow for direct electrical connection by the die attach layer, has the added feature that the die attach layer has a melting temperature and a re-melting temperature, and the re-melting temperature is higher than the initial melting temperature.
27. The LED component according to claim 26 wherein the melting temperature is below 260° C. and the re-melting temperature is above 260° C.
The LED component where the die attach layer has both a melting temperature and a higher re-melting temperature, as previously described, has the added feature that the initial melting temperature is below 260 degrees Celsius, and the re-melting temperature is above 260 degrees Celsius.
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November 21, 2014
March 21, 2017
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